CT device for imaging slices that are inclined toward the system axis

Abstract

A CT device for imaging slices that are inclined toward the system axis has an input unit for the entering the position of at least one slice that is to be imaged and that is inclined toward the system axis. A volume which completely contains the slice that is to be imaged and that is inclined toward the system axis is scanned by initially generating planar tomograms from the data acquired during the scanning of the volume, and the tomogram of a desired slice that is inclined toward the system axis is produced from these planar tomograms by multi-planar reconstruction.

We claim as our invention:  
     
       1. A computed tomography device for imaging slices that are inclined toward a system axis, comprising: 
       a measuring unit having a radiation source with a focus, at least said focus being displaceable around a system axis, and a detector system on which radiation from said radiation source is incident for irradiating an examination subject disposed between said radiation source and said detector system from a plurality of different projection angles;  
       a support adapted to receive an examination subject, said support and said measuring unit being adjustable relative to each other in a direction of said system axis, while displacing said focus, for scanning a volume of an examination subject;  
       an input unit for entering a position of at least one slice which is to be imaged and which is inclined toward said system axis;  
       a control unit connected to said input unit for relatively adjusting said measuring unit and said support in said direction of said system axis for scanning a scanned volume so that said at least one slice is completely contained in said scanned volume, said detector system detecting a plurality of projection data sets, respectively at said projection angles, during scanning of said scanned volume; and  
       an electronic computer supplied with said projection data sets for initially calculating planar tomograms from said projection data sets and for, from said planar tomograms, reconstructing said slice that is inclined toward the system axis by multi-planar reconstruction.  
     
     
       2. A computed tomography device as claimed in claim  1  further comprising a display connected at least to said input unit which displays a tomogram of said at least one slice which is inclined toward said system axis, without displaying said planar tomograms. 
     
     
       3. A computed tomography device as claimed in claim  1  wherein said input unit comprises means for entering a spatial area comprising a plurality of slices to be imaged and which are each inclined toward said system axis. 
     
     
       4. A computed tomography device as claimed in claim  1  wherein said radiation source and said detector system are operable by said control unit to produce an X-ray shadow image of an examination subject, and wherein said control unit stores said X-ray shadow image, and wherein said input unit includes a display and is connected to said control unit for retrieving said X-ray shadow image and displaying said X-ray shadow image on said display, and wherein said input unit includes a marking instrument for marking a spatial area in said X-ray shadow image on said display which includes said at least one slice which is to be imaged and which is inclined toward said system axis. 
     
     
       5. A computed tomography device as claimed in claim  4  wherein said marking instrument allows marking of a spatial area in said X-ray shadow image on said display which contains a plurality of slices to be imaged and each of which is inclined toward said system axis. 
     
     
       6. A computed tomography device as claimed in claim  5  wherein said input unit is connected to said computer and wherein said computer determines an initial position and an end position, dependent on said spatial area, for said relative movement between said measurement unit and said support for scanning said scanned volume, and supplies a signal to said control unit for controlling said relative movement to begin at said initial position and to end at said end position. 
     
     
       7. A computed tomography device as claimed in claim  1  further comprising a display connected to said computer, said displaying having an image format in which images are displayed on said display and wherein, if said slice occupies only a portion of said image format, said computer causes said slice to be displayed on said display so as to completely occupy said image format.